30 Cu/ft Caternary Arch hybrid kiln with drop down ash pit, brick grate, propane power burners, center hinge pin swing door, and rolling stoke hole doors. We used Patriot Super Duty High Alumina #1 arch, Ufala 60%, Kala Super Duty High Alumina, Seneca 60P, BNZ 2660 for the door, BNZ 2300 for cold face insulation/sub floor, and medium duty (chimney above damper) to build this kiln. The arch is 4.5” hard brick, 3” BNZ 2300, 2 layers 6# 1” fiber, chicken wire mesh, 1” of 80 lb scratch coat sanded with fiber stucco/3 gallon vermiculite custom mix for skin coat. We installed 2x 300k btu/hr burners to bring the kiln to cone 10 in 12 hrs firing time. Interior dimensions hold 2, 14x28 shelf stacks. 1/4” mild steel framing ranging from 3” to 5” give this kiln and swing door structural integrity. Rolling stoke hole doors make burning wood easy, and this kiln can burn about 1 cord of split hardwood in 15 hrs from 1500-2300 degrees with a 10 hour hold at temp to build ash.